Add ability to specify bundle exec or rake path

ATM when [building our command](https://github.com/doximity/rake-ui/blob/48bc924c0d0fd25d1f5713e64f29def96c78e1a9/app/models/rake_ui/rake_task.rb#L96) we call rake directly, which is a good assumption for most cases. However we need the ability for people to specify things like path or to use bundle exec for executing.